/**
 * Copyright (c) 2015-2017, Winter Lau (javayou@gmail.com).
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.oschina.j2cache;

import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import net.oschina.j2cache.util.SerializationUtils;

/**
 * 二级缓存接口
 * 
 * @author Winter Lau(javayou@gmail.com)
 */
public interface Level2Cache extends Cache {

	/**
	 * 读取缓存数据字节数组
	 * 
	 * @param key
	 * @return
	 */
	byte[] getBytes(String key);

	/**
	 * 同时读取多个 Key
	 * 
	 * @param keys
	 * @return
	 */
	List<byte[]> getBytes(Collection<String> keys);

	/**
	 * 设置缓存数据字节数组
	 * 
	 * @param key
	 * @param bytes
	 */
	void setBytes(String key, byte[] bytes);

	/**
	 * 同时设置多个数据
	 * 
	 * @param bytes
	 */
	void setBytes(Map<String, byte[]> bytes);

	/**
	 * 判断缓存数据是否存在
	 * 
	 * @param key
	 *            cache key
	 * @return
	 */
	@Override
	default boolean exists(String key) {
		return getBytes(key) != null;
	}

	/**
	 * Return all keys
	 *
	 * @return 返回键的集合
	 */
	@Override
	Collection<String> keys();

	/**
	 * Remove items from the cache
	 *
	 * @param keys
	 *            Cache key
	 */
	@Override
	void evict(String... keys);

	/**
	 * Clear the cache
	 */
	@Override
	void clear();

	long size();

	@Override
	default Object get(String key) {
		byte[] bytes = getBytes(key);
		try {
			return SerializationUtils.deserialize(bytes);
		} catch (IOException e) {
			throw new CacheException(e);
		}
	}

	@Override
	default Map<String, Object> get(Collection<String> keys) {
		Map<String, Object> results = new HashMap<>();
		if (keys.size() > 0) {
			List<byte[]> bytes = getBytes(keys);
			int i = 0;
			try {
				for (String key : keys) {
					results.put(key, SerializationUtils.deserialize(bytes.get(i++)));
				}
			} catch (IOException e) {
				throw new CacheException(e);
			}
		}
		return results;
	}

	@Override
	default void put(String key, Object value) {
		try {
			setBytes(key, SerializationUtils.serialize(value));
		} catch (IOException e) {
			throw new CacheException(e);
		}
	}

	@Override
	default void put(Map<String, Object> elements) {
		if (elements.size() > 0) {
			setBytes(elements.entrySet().stream().collect(Collectors.toMap(p -> p.getKey(),
					p -> SerializationUtils.serializeWithoutException(p.getValue()))));
		}
	}

}
